From 1f07386a9f09977516d2a81ba70604961221d1ef Mon Sep 17 00:00:00 2001
From: Henk Wiedig <henk@wiedig.de>
Date: Tue, 19 Nov 2024 22:13:20 +0100
Subject: [PATCH] add doubble buffering

---
 osd/util/Render_Rockchip.c | 31 ++++++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)

diff --git a/osd/util/Render_Rockchip.c b/osd/util/Render_Rockchip.c
index 76c8590..e18ac50 100644
--- a/osd/util/Render_Rockchip.c
+++ b/osd/util/Render_Rockchip.c
@@ -19,8 +19,11 @@
 
 cairo_surface_t* surface=NULL;
 cairo_surface_t* image_surface = NULL;
+cairo_surface_t* surface_shm=NULL;
+
 cairo_t* cr=NULL;
-Pixmap backbuffer_pixmap;
+cairo_t* cr_shm=NULL;
+
 
 // Define the shared memory region structure
 typedef struct {
@@ -81,17 +84,25 @@ int Init_x86(uint16_t *width, uint16_t *height) {
     }
 
     // Create a Cairo surface for the image data
-    surface = cairo_image_surface_create_for_data(
-        shm_region->data, CAIRO_FORMAT_ARGB32, shm_width, shm_height, shm_width * 4);
+    surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, shm_width, shm_width);        
     if (cairo_surface_status(surface) != CAIRO_STATUS_SUCCESS) {
         fprintf(stderr, "Failed to create Cairo surface\n");
+        return -1;
+    }
+
+    // Create a Cairo surface for the image data connecto to the shm
+    surface_shm = cairo_image_surface_create_for_data(
+        shm_region->data, CAIRO_FORMAT_ARGB32, shm_width, shm_height, shm_width * 4);
+    if (cairo_surface_status(surface_shm) != CAIRO_STATUS_SUCCESS) {
+        fprintf(stderr, "Failed to create Cairo surface_shm\n");
         munmap(shm_region, shm_size);
         close(shm_fd);
         return -1;
-    }
+    }    
 
     // Create a Cairo context
-    cr = cairo_create(surface);  
+    cr = cairo_create(surface);
+    cr_shm = cairo_create(surface_shm);
 
 }
 
@@ -175,14 +186,24 @@ void Render_x86_rect(unsigned char* rgbaData, int u32Width, int u32Height, int s
 
 void FlushDrawing_x86(){
 
+    // Copy work buffer to the display surface do avoid flickering
+    cairo_set_operator(cr_shm, CAIRO_OPERATOR_SOURCE);
+    // Copy buffer to the display surface
+    cairo_set_source_surface(cr_shm, surface, 0, 0);
+    cairo_paint(cr_shm);
+
+    cairo_surface_flush(surface_shm);
+
 }
 
 
 void Close_x86(){
     // Clean up resources
     cairo_destroy(cr);
+    cairo_destroy(cr_shm);
     cairo_surface_destroy(image_surface);
     cairo_surface_destroy(surface);
+    cairo_surface_destroy(surface_shm);
 }